In then ext generation wideband communication system, solving inter-cell interference becomes a key factor to improve throughput and average UT throughput of a user terminal (UT), and how to efficiently solve inter-cell interference faces a severe challenge.
Currently, the IEEE (Institute of Electrical and Electronics Engineers) 802.16j, advanced International Mobile Telecommunications (IMT-Advanced) system and WINNER propose to solve the problem of inter-cell interference by using methods such as interference randomization, interference coordination, interference elimination, etc. The LTE (Long Term Evolution) system, based on the methods described above, proposes to divide the coverage area of the current cell into an inner layer and an outer layer based on the strongest interference level of the UT to all adjacent cells, and solve inter-cell interference using methods of partial power control and road loss compensation. The inner layer, which is an area with weaker inter-cell interference, solve the problem of inter-cell interference using full power compensation; while the outer layer, which is an area with stronger inter-cell interference, solve the problem of inter-cell interference using methods of partial power control and road loss compensation.
In a LTE system, an interference state of a PRB (Physical Resource Block) occupied by the UT suffering from a high level of inter-cell interference is indicated in an OI report; and load negotiation is performed between different BSs (Base Station) based on the OI report such that the inter-cell interference suffered by the UT on the PRB is efficiently decreased, thereby achieving the purpose of coordinating inter-cell interference.
Relevant regulations for an OI report in the LTE system will be described below.
Each PRB is configured with an OI value, which is represented by 2 bits and divided into three levels, namely, high (00), middle (01), low (10), which represent respectively levels of inter-cell interference suffered by the PRB, i.e., high interference, middle interference, and low interference.
However, since there are four representation modes, namely, “11”, “10”, “01” and “00” for 2 bits, which may be used to represent four interference states, and only three interference states are used in the LTE system, one state will be wasted. Therefore, the LTE system fails to efficiently use resources of 2 bits in representing interference states of the PRB, thus causing waste of system resources and increasing overhead of the system.